evbarm / INTEGRATOR ifpga device_t / softc split

Hi,
because ifpgavar.h ends up being indirectly included early by
sys/device.h, the "struct device" in that file ends up being
undeclared, causing a build failure.
The attached patch tries to remedy that by doing what is known as
a "device_t / softc" split for ifpga. It does a couple of other
minor things as well:
o converts to aprint_*() print functions
o corrects three typos
These sort of changes can sometimes be tricky, and can sometimes
result in actual run-time failures even though the source builds.
Testing would therefore be beneficial in determining that I've
not broken anything which wasn't broken before... I can at least
attest that the INTEGRATOR kernel in -current now builds after
applying the attached patches, at least :)
Since I don't have the actual hardware used by the INTEGRATOR
kernel, I'm asking here for someone who can help with actually
testing these changes.
If someone would review the changes without hardware testing,
that's of course also good.
Best regards,
- Håvard